Manufacture of photographic sensitized materials.



No. 664,982. Pate nted m. a, l90l. E. momma.

MANUFACTURE 0E PHOTOGBA PHIC SENSITIZED MATERIALS.

(Applicnfion filed Oct. 10. 1899.) (No Model.) 4 Shoots-Shoot l.

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No. 664,982. Patented m. I, I90l.

' E. THORNTON. MANUFACTURE OF FHOTOGRAPHIG SENSITIZED MATERIALS.

(Applicuion filed Oct. 10, 1899.] (No Indol.) 4 Shaats-Sheat- 2.

WITNESSES. IVNVE'NTOR No. 664,982. Patented Ian. I, l90l.

J. E. THORNTON. MANUFACTURE OF PHOTOGRAPHIC SENSITIZED MATERIALS.

(Application filed Oct. 10, 1899.)

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WITNESSES.

No. 664,982. Patented. Ian. I, 190i.

J. E.-THORNTUN. MANUFACTURE OF PHUTUGRAPHIC SENSITIZ ED MATERIALS.

(Application filed Oct. 10, 1899.) (No Model.) 4 Sheets-Sheet 4.

WITN ESSES. I NV'ENTO'R :UNITED STATES PATENT OFFICE.

JOHN EDWARD THORNTON, OF MANCHESTER, ENGLAND.

MANUFACTURE OF PHOTOGRAPHlC SENSITIZED MATERIALS.

SPECIFICATION forming part of Letters Patent No.664,982, dated January 1, 1901.

Application filed October 10, 1899. Serial No. 733,155. (No specimens.)

To all whom it may concern.-

Be it known that 1, JOHN EDWARD THORN- TON, a subject of the Queen of Great Britain,

ess or method of coating photographic films,

papers, and plates with a sensitive emulsion during their manufacture.

sensitizing materials of various kinds are used according to the desired results; but a gelatino-bromid or gelatino-chlorid emulsion is most frequently used, and therefore in describing this invention I hereinafter adopt the term emulsion as sufficiently descriptive of any sensitizing material. Similarly various supports are used for the emulsion, such as celluloid or other films, papers, glass plates, sheet metal, cardboard, and the like. Hereinafter I use the term support to in clude any support.

In the manufacture of sensitive films, pa: pers, and plates it has hitherto been the custom to coat the support with a coating of the emulsion of the desired thickness at one op eration either by hand or by machine and then to allow the coating to set. This process is often accelerated by passing the support after coating into a chilling-chamber suitably cooled by ice, mechanical, or other means and then into a drying-chamber kept at a suitable temperaturewith a current of warm dry air passing through it, the dry air entering at one side and the damp or moistoned air being drawn off at the other, the means ordinarily employed for the purpose being air-propellers or fans, hot-water pipes, and other similar appliances.

I The present process of drying is a very lengthy one on account of the thickness of the film of emulsion necessary upon the support, and it involves the necessity of the sensitized coating being exposed to the air of the drying-chamber for a number of hours. For example, it is quite usual to leave the coated support in the drying-chamber from one day to the next. Attempts have been made to hasten or shorten the drying process; but it has been found impracticable to do so beyond very narrow limits, such a change in the nature of the coated product being the result as to render it unsuitable for use by making the top less soluble than the other parts and the expansion and contraction have been unequal throughout the films.

Defects are caused by the length of time now occupied in drying. Inj urious gases in the air of the drying-room cause the coating to partially decompose, fog, or produce insensitive patches, Prolonged exposure to air charged with moisture (especially in warm Weather) causes the growth of fungus or germs, which destroy the gelatin, and any change of temperature in the drying-room produces drying-marks, frilling, and uneven density in the negatives.

I have found that if the sensitive coating could be dried quickly the faults or defects caused therein by long exposure to the atmosphere of the drying-room would be eliminated, and, provided other defects did not arise, quick drying would be a distinct and valuable improvement in the manufacture of sensitive papers, films, and plates, and would have the further advantage of increasing the speed of manufacture.

This invention consists,essentially,in applying the sensitive emulsion to the support in a great nu mber of exceedingly thin or fine coats (each too thin for photographing upon) and immediately without setting or solidifying, drying each successive coat or layer rapidly or instantaneously by a blast of heated air.

It has been found that a blast of heated air, sufficiently hot to dry quickly, applied to a coating of sensitive emulsion of the usual thickness melts the coating and causes it to run, yielding an absolutely-useless result. I find, however, that the heated-air blast applied to an exceedingly thin or fine coat or layer of the sensitive emulsion produces an entirely difierent result, the moisture being almost instantly removed.

The invention will be fully described with reference to the accompanying drawings.

Figure 1 shows asectional elevation of apparatus for coating continuous films with the sensitive emulsion. Fig. 2 shows a modified arrangement of same. Fig. 3 shows an apparatus for coating plates. Fig. 4- shows a sectional elevation of apparatus for applying and drying a number of coats of the sensitive emulsion without removing the film from the machine.

For applying the invention to the coating of a sensitive emulsion upon a support of thin flexible material Asuch as paper, cellu loid, or other web material-a suitable machine is constructed with a roller B to apply the emulsion to the support A, a jacketed or heated trough O, a ductor-roller D, rotating in the trough, to convey the emulsion to the coating-roller B, an inclosed chamber E, through which the web-support when coated passes, air-ducts F, through which heated air is forced and caused to impinge upon the traveling web-support A, and guide-rollers G, placed to conduct the material over the coating-roller and through the drying-chamber E. A straight dryingchamber E, as shown in Fig. 1, or a curved or cylindrical drying chamber E, as shown in Fig. 2, may be employed.

For the coating of a stiif or rigid support I-Isuch as plates of glass, celluloid, mica, or the like-the machine is constructed with a traveling carrying-band K, passing over guide-rollers L and provided with a number of transverse ribs it, by which the plates H are held in position thereon. Above or in close proximity to the traveling carrier-band K is placed the trough or box M for containing the emulsion, and over the traveling carrier-band K is formed the drying-chamber N, with the air-d ucts O,through which the heated air is forced upon the coated plates as they are carried through. In the emulsion box or trough M a revolving silver-gauze cylinder P is placed, which rotates in the emulsion, and

.inside the gauze cylinder is placed a flat air tube or nozzle R, of the same width as the plates, through which a blast of air is forced. In the side of the trough or box M opposite the air-tube a slit is formed through which the emulsion adhering to the silver gauze of the cylinder P is blown in a fine spray onto the plates H, carried by the traveling carrierband K.

An exceedingly-fine layer of coating of the emulsion is deposited on the support A or H and dried as such passes through the machine, and the process is repeated again and again until the finished coating of the sensitive emulsion is of the desired thickness. It will be necessary in this manner to apply about from ten to twenty coats to obtain a thickness equal to that usually applied at the one operation.

The whole length of time taken to successfully apply and dry the successive thin coats of the sensitive emulsion is infinitely less than the time now taken to dry a single coating having the same finished thickness. In fact, I find that the film can be completed in a few minutes, whereas it has hitherto occupied many hours.

Any other suitable appliance may be eniployed for applying the very thin coating to the support, and the sensitive film may be dried either by heated air or by contact with a steam-heated cylinder or hot rollers. The time of drying may occupy seconds or minutes, according to the thickness of coating applied, the temperature of the air, the apparatus employed, and the rate of travel of the support.

The paper or flexible film support may be reeled, as shown, after each coat and passed repeatedly through the apparatus, or a number of coating-rollers and drying chambers or cylinders may be arranged in one machine, (see Fig. 4,) so that the support maybe fully coated with the requisite number of line coats at one operation.

In Fig. 4 the apparatus is made up of any number of sections, comprising a coatingroller 13, trough G, ductor-roller D to apply the emulsion to the coating-roller, drying chamber E into which the heated blast of air is injected by the nozzle on the perforated pipe F,and guide-rollers G and G The roller G may be heated if desired. Likewise a number of spraying apparatus may be used for plates. This method of manufacturing sensitive films upon flexible or rigid supports will be found to be of enormous value when dealing with gelatino-bromid emulsions of a high degree of sensitiveness, such as are used for extremely-rapid instantaneous work. The difficulties in producing perfect results and products with good keeping qualities with these delicate emulsions have hitherto been greatly increased by the changes set up therein during the hitherto lengthy process of drying thick coatings, such as have always been used, which was due largely to atmospheric conditions producing chemical changes in the sensitive coating. By my invention these difficulties are practically removed, the coatings being rapidly dried, so as to prevent the aforesaid chemical changes,accompanied, as they are, by decomposition of the gelatine, taking place.

WVhat I claim as my invention, and desire to protect by Letters Patent, is-

1. In the manufacture of photographic films plates or papers, the process which consists in building up the sensitive film by applying to the support a great number of very thin coats, each too thin to photograph upon of the sensitive emulsion, and immediately pass ing same through a heated atmosphere and instantaneously drying, before the spreading of the next substantially as described.

2. The process of manufacturing photographic films plates or papers, consisting in building up the sensitive film thereon by applying to the support a great number of very thin coats of sensitive emulsion, immediately causing a current of heated air to impinge upon the thin sensitive coat, and instantaneously dry it, substantially as described.

3. The process of manufacturing photographic films plates or papers, by spreading a very thin coat of the sensitive emulsion thereon, immediately treating such thin coat with a blast of heated air whereby it is almost instantaneously dried, again spreading on the first coat another very thin coat of sensitive emulsion, treating such second coat with a blast of heated air, again spreading a very thin coat of the sensitive emulsion and 10 drying same, and so on until a sensitive film is built up upon the support of sufficient thickness substantially as described.

In witness whereof Ihave hereunto signed my name in the presence of two subscribing witnesses. 7

JOHN EDWARD THORNTON.

Witnesses:

J. OWDEN OBRIEN, JOSEPH BATES. 

